1. Field of the Invention
This invention relates to a method of automatically performing the calculations usually performed by the printer operator in laying out a print job so as to optimize the location of the printed image on the paper media, for example minimizing the amount of trimming required after printing on media larger than the desired final size. More particularly, the invention relates to automatically laying out the image size and location on the page so that, even in duplex printing, the amount of post-printing handling, such as trimming, is minimized.
2. Brief Description of the Related Art
The invention relates to apparatus and methods for production of printed images on paper media. For the sake of clarity, the four edges of such paper media may be referred to herein as the leading edge, the trailing edge and two lateral edges, in reference to the direction of travel through the printer. The printed output is referred to in terms of a print area, defined by a length and width of the finished printed product, after post-printing trimming.
Many digital printers and copiers are capable of producing a finished product having the appearance of documents produced using ink-based, offset printing techniques. Such output includes brochures and the like, where the customer desires that the entire page be printed, with no unprinted margins or edges. One option for producing such documents is to print on oversize media and trim the four unprinted edges off the printed output to yield the finished product. This method produces an acceptable product and, indeed, may be requested by some customers. However, it introduces an additional production step, requiring an operator to setup a post-printing trimming device and trim the printed output to desired dimensions of the final product. In addition to increasing labor costs and production time, the additional operator intervention required introduces the possibility of operator error, resulting in expensive wasted print runs.
In setting up a print job that will be trimmed after printing, the operator is required to calculate a layout that will center the image, resulting in the same margin on the leading edge and trailing edge, on both the front and back sides of the page, followed by trimming to remove the portion outside the margin on both edges. Additional problems arise when the operator is required to print on odd-size media, for example 7″ by 9″ rather than 8½″ by 11″ media. This situation is especially problematic when the job must be printed on larger media than the customer wants delivered as the finished product. In this situation, the operator is required to perform sophisticated layout work, manually calculating the image shift required to place the image in the appropriate position on the media. In the case of simplex (single-sided) copying, the operator is required to shift the image only past any enforced printer margin, for example, a 1/10″ enforced margin on the leading edge of the page, followed by appropriate trimming on all four edges to yield that finished product. In duplex (two-sided) printing, however, the image must be shifted so that the image on the first side of the page and the image on the second side of the page coincide in the same area, so that none of the image on either side is lost in trimming. For example, in the case of printing a 7″×9″ image on 8.5″×11″ paper, the calculations would involve shifting the image from each edge, i.e., by shifting the x-origin by (8.5−7)/2 inches and the y-origin by (11−9)/2 inches. The printed output must then be trimmed to remove the portion of the paper outside these shift values. Therefore, the calculations involved in such layout work must be preserved, written down and sent to the person performing the trimming, along with the finished printing output. The trimming operator must then replicate the calculations exactly in setting up the trimming device, or the finished copy output will be trimmed incorrectly, ruining the entire print job. Each of the steps in the layout process and the setup operations on the trimming device are time-consuming, labor-intensive and are potential sources of operator error.
Many high-end printers and copiers can be enabled to print “full bleed,” that is, they may be setup to print to the very edge of the paper medium. However, because of quality concerns, many electrophotographic marking engines do not allow full bleed printing on all four edges of the medium. These quality concerns relate mainly to the retention of toner on the leading edge of the media. Prior to fusing, the toner is held in association with the paper by electrostatic forces. However, the toner does not bind as well at the edges of the media, particularly because it is more susceptible to being shaken off the paper when the leading edge is contacted by the fuser nip rollers and, therefore when the leading edge enters the fuser nip rollers, the leading edge of the page is particularly susceptible to smearing or other problems resulting in poor print quality. Therefore, in order to avoid such problems, many printers only allow full-bleed printing on the trailing and lateral edges, with an enforced printer margin on the leading edge. However, in duplex printing, the leading edge of the first side of the page does not coincide with the leading edge of the second or reverse side of the page. In fact, the leading edge of the first side of the page becomes the trailing edge of the second side of the page. This makes it impossible to simply print to the limit of the enforced margin on the leading edge on both sides and trim the finished product, as the trimming will remove a portion of the image on each side of the page.
By taking advantage of the ability of such printers to print to the very edge of the page, it is possible to locate the print area on the page such that post-printing trimming is minimized. In some instances, this may require no more than centering the image between the leading and trailing edges with full-bleed printing on the lateral edges, necessitating trimming of only two sides. Such an approach is equally useful in single-sided and double-sided printing. Alternatively, in single-sided printing, it may be possible to print full-bleed on the trailing and lateral edges, trimming only the leading edge.
Additionally, one may use the different size media available, selecting the media on which the print area fits optimally. By taking advantage of the ability of the printer to print full bleed, in conjunction with the ability to shift and rotate the image, it is possible to optimize the location of the image on the page. As used herein, optimizing the location of the image on the page includes minimizing post-printing trimming, as well as other beneficial results of the invention, such as allowing processing of print jobs on available media by manipulating the location of the image on the page.
Therefore, in view of these disadvantages of the prior art and current practices there is a need in the art for a printer that takes advantage of the full-bleed printing capability of current printers and automatically performs the necessary layout calculations. Therefore, it is an object of the present invention to take advantage of the ability of such printers to print to the very edge of the page, locating the print area on the page such that post-printing trimming is minimized.
It is an additional object of the invention to use the different size media available, selecting the media on which the print area its optimally, for example by rotating the print area if necessary and locating the print area so as to minimize post-printing trimming.
These and other objects and advantages of the invention are illustrated and clarified by the following detailed description of preferred embodiments of the invention, with appropriate reference to the figures described below.